# Why the whole wire moves when lorentz force acts?

We know that magnitute of lorentz force is directly proportional to the current in the current carrying wire.
But since the force is acting on the charges,shouldn't they get exited or thrown out when the magnitude of the force crosses the binding force between them and opposite charges?Please tell me if such phenomenon occurs.
Also when electrons move in a wire we usually say positve charges are moving in opposite directions,though not actually,I am talking about holes moving.So should the lorentz force also act on the positive charges?

• Can one produce field emission using a transformer? Yes, that's usually how it's done. Normally we do try to avoid field emission, though, since it's rarely useful and it's actually quite limiting in building accelerator cavities. Commented Jul 6, 2015 at 17:49

## 1 Answer

Each charge carrier in the wire generates its own magnetic field and, as you pointed out, the overall magnetic field generated by the wire is somehow proportional to the current flow within the wire. And yes, the charge carriers do feel their own magnetic field, but usually this is a negligible effect and almost never enough for the particles to "break" the wire and exit out.

,shouldn't they get exited or thrown out when the magnitude of the force crosses the binding force between them and opposite charges?

If the magnitude of the applied force due to their own magnetic field were so strong to break the normal reaction of the wire upon the particles themselves then yes, this might happen. But for standard particles and standard wires this is just never the case. Wires are usually built taking into account all the possible counter-terms generated by the self-interactions. Notice that in general everything that is allowed by nature to occur does in fact occur, but the overall contributions and effects that you see are only the ones of the prominent forces.

Furthermore

Also when electrons move in a wire we usually say positve charges are moving in opposite directions,though not actually,I am talking about holes moving.So should the lorentz force also act on the positive charges?

the Lorentz force acts on every charge, whether positive or negative. Then particles move according to the Newton's law, taking into account all possible minus signs. Holes are not actual particles: what happens is that the electrons move away and leave their original positions, which can be replaced by other electrons and so on and so forth. The overall effect is as if there were positive charges moving towards the opposite direction, but that is just a pictorial representation to take into account the displacement of the single electrons from the original position.

• I read the very basic concept of special theory of relativity applied in electromagnetism which tells me that when charged particles are at rest it will experience lorentz force since it is moving in opposite direction to the other external moving charged particles.Can this be applied to the positive charges as I mentioned above.Though positive charges are not themselves moving but when an electron move a temporary positive charge is created at that place which in the process of moving of electrons are considered as if positive charges are moving Commented Jul 6, 2015 at 15:17
• Can the case above as I mentioned in comment applicable for externally applied magnetic field. Commented Jul 6, 2015 at 15:27
• Am I correct to say that for two current carrying wires the lorentz force acts as if individual charged particles of one wire are contributing its force on individual charged particles of other wire thus again there is negligible effect for particles to break through.Or by negligible effect you mean net effect is negligible. Commented Jul 6, 2015 at 15:44
• You are making confusion among too many things at a time. Choose the particle you want to describe and your reference frame; then, whether classical or relativistic, write down the equations and find the solutions. About the hole theory, no, no positive particle is "created" in the wire, it is just a pictorial representation. And yes, you can apply all this to magnetic fields and all the rest, just changing the right hand side of the equation of motion (but that's too many things at a time, open a different question in case). Commented Jul 6, 2015 at 16:18